Spatial analysis of the tumor immune microenvironment in Biliary Tract Cancer

Background: Biliary Tract Cancer (BTC) is a highly aggressive and often lethal malignancy. Immunotherapies are now regularly used for therapy, however the understanding of the BTC tumor immune microenvironment is still lacking.

Methods: Tissue Microarrays (TMA) from 21 BTC patients were analyzed using imaging mass cytometry. We employed an analysis approach to understand the immune architecture on a single-cell and spatial level, taking into account regional features such as tumor organization. Such an approach has previously allowed patient classification in HCC, and was linked to the outcome of immunotherapy.

Results: 21 BTC samples were differentiated into 3 immunotypes (IT) based on CD8T cell infiltration and relative localization in tumor stroma or parenchyma: enriched (n=5, 23%), compartmentalized (n=6, 28%) and depleted (n=11, 52%). Differential immune cell associations were found: M2-like Macrophages (CD204+CD68+) cells were higher in depleted BTC tissue as compared to compartmentalized IT (99,55/mm2 vs 72,46/mm2; p=0,0001) and FoxP3 regulatory T cells were more abundant in depleted IT against enriched IT (17,81/mm2 vs 9,51/mm2; p=0,0001), CD45+CD20+B cells were seen more in enriched IT versus the depleted IT (155,9/mm2 vs 0,39/mm2; p=0,0001) and CD68+CD163+and CD68+CD15+macrophages were enriched in depleted versus enriched IT tissue (112,14/mm2 vs 46,34/mm2; p=0,0001). Similarly, CD8+CD45RO+memory T cells were present in enriched tissue more than in depleted ones (1227/mm2 vs 40,7/mm2; p=0,0001).

Conclusion: The heterogeneity of the tumor immune microenvironment in BTC can be described using a highly multiplexed single-cell analysis of the immune architecture

Publication History

Article published online:
20 January 2025